This invention relates to a method and system for rapidly and accurately analyzing ambulatory electrocardiographic tape recordings taken over substantial periods of time, such as 24 hours. Heretofore magnetic tape recordings of ambulatory electrocardiograms, such as provided by Holter tapes have been accomplished by various computer assisted techniques. Holter is the trademark of Extracorporeal Medical Specialties Inc., King of Prussia, Pa. for a system of electromagnetic tape recordings of electrocardiograms. Performing computer assisted analysis is extremely laborious and time consuming and in some instances does not provide completely satisfactory results. An object of this invention is to provide a rapid, convenient and time-saving method and system for analyzing magnetic tape electrocardiograms, which provide substantially accurate results.